OA. Positively charged particles are attracted to negatively charged particles.
OB. Negative and positive electric charges build up in different regions
of a clOud
C. Electrons flow from an outlet into a toaster, causing it to heat a
slice of bread.
OD. A person rubs a shoe on a rug, causing extra electrons to be
transferred to the shoe.

Complete question:

Which is an example of current electricity?

A. Positively charged particles are attracted to negatively charged

particles.

B. Negative and positive electric charges build up in different regions

of a cloud.

C. Electrons flow from an outlet into a toaster, causing it to heat a

slice of bread.

D. A person rubs a shoe on a rug, causing extra electrons to be

transferred to the shoe.

The correct example of current electricity is C. Electrons flow from an outlet into a toaster, causing it to heat a slice of bread.

Explanation:  

Current electricity refers to the flux of charged particles through a conductor material per unit of time. In general, when we refer to electric current we are talking about the electron flux. Electric energy originates from the difference of electrical potential between two points when they get in contact through a conductor. This contact provokes an electrical current  that consists of the transmission of negative charges called electrons through conductor materials such as metals from the source of generation to the point of consumption.

In the exposed example, the source of electrons is the outlet, while the point of electron consumption is the toaster. In this last artifact, electrical energy is transformed into heat to toast the bread.

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers